According to the study, 40% of infective endocarditis cases are caused by oral bacteria.

However, the authors did point out that their data does not establish a causal association.

A team of international researchers, led by Martin Thornhill, a professor of translational research in dentistry at the University of Sheffield School of Clinical Dentistry, looked to investigate changes in the prescribing of antibiotic prophylaxis and the incidence of infective endocarditis since the introduction of the 2008 NICE guidelines.

Thornhill said: ‘We hope that our data will provide the information that guideline committees need to re-evaluate the benefits, or not, of giving antibiotic prophylaxis.’

Recent changes in antibiotic prophylaxis guidelines in the US and Europe have reduced the number of patients for whom antibiotic prophylaxis is recommended.

The study discovered that infective endocarditis cases have increased above the expected trend since the NICE guidelines were introduced.

By March 2013, this meant approximately an extra 35 cases per month.

This increase in infective endocarditis was significant for individuals at high and lower risk for the condition.

The researchers also identified that the prescribing of antibiotic prophylaxis fell by 89% from 10,900 prescriptions a month, before the 2008 guidelines, to 1,235 a month by March 2008.

Thornhill emphasized that dentists and other healthcare professionals should wait for the guideline committees to evaluate the evidence and give their advice before changing their current practice.

He continued: ‘In the meantime, healthcare professionals and patients should focus on maintaining high standards of oral hygiene.

‘This will reduce the number of bacteria in the mouth that have the potential to cause (infective endocarditis) and reduce the need for invasive dental procedures to be performed.’

The researchers completed a retrospective secular trend study and analysed data for the prescription of antibiotic prophylaxis from 1 January 2004, to 31 March 2013, and also hospital discharge episode statistics for patients with a primary diagnosis of infective endocarditis from 1 January 2000, to 31 March 2013.

Published online in Lancet (November 18, 2014), the study claims to be the largest and most comprehensive to be conducted with regard to the NICE guidelines, which recommended that dentists should no longer give antibiotics before invasive treatments to people considered at risk for infective endocarditis.

The research was funded by a grant from Heart Research UK, Simplyhealth, and the National Institute for Dental and Craniofacial Research.